This application is related to and claims priority from Japanese Patent Application No. 2001-57252 filed on Mar. 1, 2001, the content of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a vehicle air conditioner having a single air-conditioning unit for performing air-conditioning operation for both of a front seat side and a rear seat side in a passenger compartment.
2. Description of Related Art
In a conventional vehicle air conditioner disclosed in U.S. Pat. No. 5,086,628, a single air-conditioning unit performs air-condition operation for both sides of a front seat and a rear seat in a passenger compartment. In this air-conditioning unit, an air passage is divided into a front air passage and a rear air passage at a downstream air side of a cooling heat exchanger, so that air is blown to the front seat side through the front air passage, and air is blown to the rear seat side through the rear air passage. Further, an opening/closing door is provided in the rear air passage, and air blown to the rear seat side is switched by the opening/closing door. When the opening/closing door is opened so that air is blown to the rear seat side, an air-blowing amount of the air-conditioning unit is increased.
However, a specific control for increasing the air amount is not disclosed in the above air conditioner. Because a comfortable amount of air blown into the passenger compartment is changed in accordance with a condition of the air conditioner, an amenity in the passenger compartment is worsened when an increased rate of the air-blowing amount is not suitably controlled.
In view of the foregoing problems, it is an object of the present invention to provide a vehicle air conditioner with a front air passage and a rear air passage, which suitably controls an increase amount of an air-blowing amount while air is blown to a rear seat side of a passenger compartment through the rear air passage, so that an amenity in the passenger compartment is improved.
According to the present invention, a vehicle air conditioner includes a blower for blowing air into the passenger compartment through the front air passage and the rear air passage, an air-amount adjustment unit for adjusting an amount of air blown at least toward the upper side of the front seat in the passenger compartment, an opening/closing unit for opening and closing the rear air passage, air-amount determination means for determining an air-blowing amount of the blower, and air-amount correction means for increasing the air-blowing amount determined by the air-amount determination means when the rear air passage is opened by the opening/closing unit. In the vehicle air conditioner, the air-amount correction means sets an increase amount of the air-blowing amount, determined by the air-amount determination means, to be larger when the amount of air blown to the upper side of the front seat is larger than a predetermined amount, than that when the amount of air blown to the upper side of the front seat is smaller than the predetermined amount. Generally, a passenger is readily sensed when an air amount blown to the upper side of the passenger is changed, as compared with a case where an air amount blown to the lower side of the passenger is changed. In the present invention, because the increase amount of the air-blowing amount of the blower is suitably controlled according to the amount of air blown to the upper side of the passenger on the front seat, the amenity of the passenger on the front seat can be maintained even when air is blown to the rear seat side.
Preferably, in a face mode where air is blown from a face opening of the front air passage, the amount of air blown toward the upper side of the front seat is larger than the predetermined amount. On the other hand, in a bi-level mode where air is blown from both of the front face opening and the front foot opening, the amount of air blown toward the front seat is smaller than the predetermined amount. Accordingly, the increase amount of the air-blowing amount can be increased in the face mode.
When the air outlet mode is automatically set based on a target temperature of air blown toward the front seat in the passenger compartment, the face mode is set when the target temperature is lower than a first predetermined temperature, a foot mode is set when the target temperature is higher than a second predetermined temperature higher than the first predetermined temperature, and the bi-level mode is set when the target temperature is in an area between the first predetermined temperature and the second predetermined temperature. Accordingly, while air is blown toward the rear seat, the air amount can be increased in the face mode and in the foot mode.
Alternatively, when the air outlet mode is manually set by a passenger in the passenger compartment, the air-amount correction means sets the increase amount of the air-blowing amount at a small value in the foot mode, sets the increase amount of the air-blowing amount at a middle value larger than the small value in the bi-level mode, and sets the increase amount of the air-blowing amount at a large value larger than the middle value in the face mode. Therefore, while air is blown toward the rear seat in the passenger compartment, the air amount can be suitably increased in accordance with the manually-set air outlet mode.
Further, the vehicle air conditioner includes an air mixing door for adjusting a ratio between an air amount passing through a heating heat exchanger and an air amount bypassing the heating heat exchanger, and door open-degree determination means for increasing an open degree of the air mixing door as the target temperature increases. The air-amount correction means increases the increase amount the air-blowing amount, determined by the air-amount determination means, larger in a small open-degree area and a large open-degree area of the air mixing door, than that in a middle open-degree area between the small open-degree area and the large open-degree area. Thus, the air amount can be suitably increased in accordance with the open degree of the air mixing door, while air is blown toward the rear seat in the passenger compartment.